---
title: "Overview"
description: "Build production ready smart glasses apps in minutes."
---

## How MentraOS Works

MentraOS is the smart glasses operating system. It allows third party apps to run on smart glasses.

Users install the Mentra app on their phone, connect their glasses, and run apps.

Developers build apps that users can install (from a web link or the Mentra Store).

Third party apps run in the cloud and have a low-latency connection to all the smart glasses hardware. Developers can call functions in their web application to a picture, listen to microphone data, or display information on users' smart glasses.

## Why Use MentraOS

MentraOS provides:

- **Universal** - Works with glasses from multiple manufacturers including Vuzix, Even Realities, Mentra, and a number of new glasses in 2026.
- **Powerful** - Audio, camera, display, sensors, and AI integration.
- **Simple** - Server-side apps using familiar web technologies.
- **Open Source** - 100% open, MentraOS is the industry standard OS for smart glasses.

## Hello World MentraOS App

Here's a MentraOS app that shows "Hello World" on a smart glasses display:

```typescript
import { AppServer } from '@mentra/sdk';

class MyApp extends AppServer {
  protected async onSession(session, sessionId, userId) {
    // Display "Hello World" on the glasses
    session.layouts.showTextWall("Hello World from MentraOS!");
    
    // Log when user speaks
    session.events.onTranscription((data) => {
      console.log(`User said: ${data.text}`);
    });
  }
}

const app = new MyApp({
  packageName: 'com.example.myapp',
  apiKey: process.env.MENTRA_API_KEY,
  port: 3000
});

app.start();
```

That's it! This app will:

1. Connect to a user's smart glasses when they launch your app
2. Display "Hello World from MentraOS!" on their glasses display
3. Log everything the user says to your server console

## What You Could Build

With MentraOS, developers have built:

- **Fitness coaches** with workout guidance
- **Live captions** for the deaf/HoH
- **Industrial inspection tools** with camera glasses
- **Video streaming platforms** for content creators

## Next Steps

🚀 Ready to build your first app? Check out the [Quickstart](/app-devs/getting-started/quickstart).
